Lipid-based compositions of antiinfectives for treating pulmonary infections and methods of use thereof

ABSTRACT

A system for treating or providing prophylaxus against a pulmonary infection is disclosed comprising: a) a pharmaceutical formulation comprising a mixture of free antiinfective and antiinfective encapsulated in a lipid-based composition, and b) an inhalation delivery device. A method for providing prophylaxis against a pulmonary infection in a patient and a method of reducing the loss of antiinfective encapsulated in a lipid-based composition upon nebulization comprising administering an aerosolized pharmaceutical formulation comprising a mixture of free antiinfective and antiinfective encapsulated in a lipid-based composition is also disclosed.

RELATED APPLICATIONS

This application claims the benefit of priority to U.S. ProvisionalPatent Application Ser. No. 60/748,468, filed Dec. 8, 2005, which ishereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

According to the World Health Organization, respiratory diseases are thenumber one cause of world-wide mortality, with at least 20% of theworld's population afflicted. Over 25 million Americans have chroniclung disease, making it the number one disabler of American workers(>$50B/yr), and the number three cause of mortality.

Currently, most infections are treated with oral or injectableantiinfectives, even when the pathogen enters through the respiratorytract. Often the antiinfective has poor penetration into the lung, andmay be dose-limited due to systemic side-effects. Many of these issuescan be overcome by local delivery of the antiinfective to the lungs ofpatients via inhalation. For example, inhaled tobramycin (TOBI®, ChironCorp, Emeryville, Calif.), is a nebulized form of tobramycin, that hasbeen shown to have improved efficacy and reduced nephro- andoto-toxicity relative to injectable aminoglycosides. Unfortunately,rapid absorption of the drug necessitates that the drug product beadministered twice daily over a period of ca., 20 min peradministration. For pediatrics and young adults with cystic fibrosisthis treatment regimen can be taxing, especially when one takes intoaccount the fact that these patients are on multiple time-consumingtherapies. Any savings in terms of treatment times would be welcomed,and would likely lead to improvements in patient compliance. Achievingimproved compliance with other patient populations (e.g., chronicobstructive pulmonary disease (COPD), acute bronchial exacerbations ofchronic bronchitis) will be critically dependent on the convenience andefficacy of the treatment. Hence, it is an object of the presentinvention to improve patient compliance by providing formulations withsustained activity in the lungs. Sustained release formulations ofantiinfectives are achieved by encapsulating the antiinfective in aliposome. Improving pulmonary targeting with sustained releaseformulations would further improve the therapeutic index by increasinglocal concentrations of drug and reducing systemic exposure.Improvements in targeting are also expected to reduce dose requirements.

Achieving sustained release of drugs in the lung is a difficult task,given the multiple clearance mechanisms that act in concert to rapidlyremove inhaled drugs from the lung. These clearance methods include: (a)rapid clearance from the conducting airways over a period of hours bythe mucociliary escalator; (b) clearance of particulates from the deeplung by alveolar macrophages; (c) degradation of the therapeutic bypulmonary enzymes, and; (d) rapid absorption of small molecule drugsinto the systemic circulation. Absorption of small molecule drugs hasbeen shown to be nearly quantitative, with an absorption time forhydrophilic small molecules of about 1 hr, and an absorption time forlipophilic drugs of about 1 min.

For TOBI® the absorption half-life from the lung is on the order of 1.5hr. High initial peak concentrations of drug can lead to adaptiveresistance, while a substantial time with levels below or near theeffective minimum inhibitory concentration (MIC), may lead to selectionof resistant phenotypes. It is hypothesized that keeping the level ofantiinfective above the MIC for an extended period of time (i.e.,eliminating sub-therapeutic trough levels) with a pulmonary sustainedrelease formulation may reduce the potential for development ofresistant phenotypes. Hence, it is a further object of the presentinvention to maintain the ratio of the area under the lungconcentration/time curve to the MIC at 24 hr (i.e., the AUIC), not onlyat an adequate sustained therapeutic level, but above a critical level,so as to reduce the potential for selection of resistant strains.

It is assumed that only the “free” (un-encapsulated) drug hasbactericidal activity. One potential disadvantage of liposomal sustainedrelease formulations is that the encapsulation of drug in the liposomalformulation decreases the concentration of free drug reaching the lungpathogens, drug which is needed to achieve efficient killing of bacteriaimmediately following administration. Hence, it is further an object ofthe present invention to provide a formulation that contains sufficientfree drug, to be bactericidal immediately following administration.

The disclosures of the foregoing are incorporated herein by reference intheir entirety.

SUMMARY OF THE INVENTION

It is an object of the present invention to use lipid-based compositionencapsulation to improve the therapeutic effects of antiinfectivesadministered to an individual via the pulmonary route.

The subject invention results from the realization that administering apharmaceutical composition comprising both free and liposomeencapsulated antiinfective results in improved treatment of pulmonaryinfections.

In one aspect, the present invention relates to a system for treating orproviding prophylaxis against a pulmonary infection, wherein the systemcomprises a pharmaceutical formulation comprising mixtures of free andlipid-based composition encapsulated antiinfective, wherein the amountof free antiinfective is sufficient to provide for immediatebactericidal activity, and the amount of encapsulated antiinfective issufficient to provide sustained bactericidal activity, and reduce thedevelopment of resistant strains of the infectious agent, and aninhalation delivery device.

The free form of the antiinfective is available to provide a bolus ofimmediate antimicrobial activity. The slow release of antiinfective fromthe lipid-based composition following pulmonary administration isanalogous to continuous administration of the antiinfective, therebyproviding for sustained levels of antiinfective in the lungs. Thesustained AUC levels provides prolonged bactericidal activity betweenadministrations. Further, the sustained levels provided by the releaseof antiinfective from the lipid-based composition is expected to provideimproved protection against the development of resistant microbialstrains.

Combinations of free and encapsulated drug can be achieved by: (a)formulation of mixtures of free and encapsulated drug that are stable tothe nebulization; (b) formulation of encapsulated drug which leads toburst on nebulization.

The ratio of free to encapsulated drug is contemplated to be betweenabout 1:100 w:w and about 100:1 w:w, and may be determined by theminimum inhibitory concentration of the infectious agent and thesustained release properties of the formulation. The ratio of free toencapsulated drug can be optimized for a given infectious agent and drugformulation based on known pharmacodynamic targets for bacterial killingand prevention of resistance. Schentag, J. J. J. Chemother. 1999, 11,426-439.

In a further embodiment, the present invention relates to theaforementioned system wherein the antiinfective is selected from thegroup consisting of antibiotic agents, antiviral agents, and antifungalagents. In a further embodiment, the antiinfective is an antibioticselected from the group consisting of cephalosporins, quinolones,fluoroquinolones, penicillins, beta lactamase inhibitors, carbepenems,monobactams, macrolides, lincosamines, glycopeptides, rifampin,oxazolidonones, tetracyclines, aminoglycosides, streptogramins, andsulfonamides. In a further embodiment, the antiinfective is anaminoglycoside. In a further embodiment the antiinfective is amikacin,gentamicin, or tobramycin.

In a further embodiment, the lipid-based composition is a liposome. In afurther embodiment, the liposome comprises a mixture of unilamellarvesicles and multilamellar vesicles. In a further embodiment, theliposome comprises a phospholipid and a sterol. In a further embodiment,the liposome comprises a phosphatidylcholine and a sterol. In a furtherembodiment, the liposome comprises dipalmitoylphosphatidylcholine (DPPC)and a sterol. In a further embodiment, the liposome comprisesdipalmitoylphosphatidylcholine (DPPC) and cholesterol.

In a further embodiment, the present invention relates to theaforementioned system wherein the antiinfective is an aminogylcoside andthe liposome comprises DPPC and cholesterol. In a further embodiment,the antiinfective is amikacin, the liposome comprises DPPC andcholesterol, and the liposome comprises a mixture of unilamellarvesicles and multilamellar vesicles.

In a further embodiment, the present invention relates to theaforementioned system, wherein the ratio by weight of freeantiuinfective to antiinfective encapsulated in a lipid-basedcomposition is between about 1:100 and about 100:1. In a furtherembodiment, the ratio by weight is between about 1:10 and about 10:1. Ina further embodiment, the ratio by weight is between about 1:2 and about2:1.

In another embodiment, the present invention relates to a method fortreating or providing prophylaxis against a pulmonary infection in apatient, the method comprising: administering an aerosolizedpharmaceutical formulation comprising the antiinfective to the lungs ofthe patient, wherein the pharmaceutical formulation comprises mixturesof free and lipid-based compostion encapsulated antiinfectives, and theamount of free antiinfective is sufficient to provide for bactericidalactivity, and the amount of encapsulated antiinfective is sufficient toreduce the development of resistant strains of the infectious agent.

In a further embodiment, the aforementioned method comprises firstdetermining the minimum inhibitory concentration (MIC) of anantiinfective for inhibiting pulmonary infections, and wherein theamount of free antiinfective is at least 2 times the MIC, preferablygreater than 4 times the MIC, and preferably greater than 10 times theMIC of the antiinfective agent, where the MIC is defined as either theminimum inhibitory concentration in the epithelial lining of the lung,or alternatively the minimum inhibitory concentration in the solidtissue of the lung (depending on the nature of the infection).

In a further embodiment, the present invention relates to theaforementioned method, wherein the aerosolized pharmaceuticalformulation is administered at least once per week. In a furtherembodiment, the present invention relates to the aforementioned method,wherein the antiinfective is selected from the group consisting ofantibiotic agents, antiviral agents, and antifungal agents. In a furtherembodiment, the antiinfective is an antibiotic selected from the groupconsisting of cephalosporins, quinolones, fluoroquinolones, penicillins,beta lactamase inhibitors, carbepenems, monobactams, macrolides,lincosamines, glycopeptides, rifampin, oxazolidonones, tetracyclines,aminoglycosides, streptogramins, and sulfonamides. In a furtherembodiment, the antiinfective is an aminoglycoside. In a furtherembodiment, the antiinfective is amikacin, gentamicin, or tobramycin.

In a further embodiment, the lipid-based composition is a liposome. In afurther embodiment, the liposome encapsulated antiinfective comprises aphosphatidylcholine in admixture with a sterol. In a further aspect, thesterol is cholesterol. In a further aspect, the liposome encapsulatedantiinfective comprises a mixture of unilamellar vesicles andmultilamellar vesicles. In a further aspect, the liposome encapsulatedantiinfective comprises a phosphatidylcholine in admixture withcholesterol, and wherein the liposome encapsulated antiinfectivecomprises a mixture of unilamellar vesicles and multilamellar vesicles.

The ratio of the area under the lung concentration/time curve to the MICat 24 hr (i.e., the AUIC) is greater than 25, preferably greater than100, and preferably greater than 250.

The therapeutic ratio of free/encapsulated drug and the required nominaldose can be determined with standard pharmacokinetic models, once theefficiency of pulmonary delivery and clearance of the drug product areestablished with the aerosol delivery device of choice.

In one aspect, the present invention relates to a method of treating apatient for a pulmonary infection comprising a cycle of treatment withlipid-based composition encapsulated antiinfective to enhance bacterialkilling and reduce development of phenotypic resistance, followed by acycle of no treatment to reduce the development of adaptive resistance.The treatment regimen may be determined by clinical research. In oneembodiment, the treatment regime may be an on-cycle treatment for about7, 14, 21, or 30 days, followed by an off-cycle absence of treatment forabout 7, 14, 21, or 30 days.

In another aspect, the present invention relates to a method forreducing the loss of antiinfective encapsulated in lipid-basedcompositions upon nebulization comprising administering theantiinfective encapsulated in lipid-based compositions with freeantiinfective.

The systems and methods of the present invention are useful fortreating, for example, lung infections in cystic fibrosis patients,chronic obstructive pulmonary disease (COPD), bronchiectasis, acterialpneumonia, and in acute bronchial exacerbations of chronic bronchitis(ABECB). In addition, the technology is useful in the treatment ofintracellular infections including Mycobacterium tuberculosis, andinhaled agents of bioterror (e.g., anthrax and tularemia). Thetechnology may also be used as a phophylactic agent to treatopportunistic fungal infections (e.g., aspergillosis) inimmunocompromised patients (e.g., organ transplant or AIDS patients).

With bacteria and other infective agents becoming increasingly resistantto traditional treatments, new and more effective treatments forinfective agent related illnesses are needed. The present inventionaddresses these issues by providing a system comprising a pharmaceuticalcomposition comprising both free and lipid-based compositionencapsulated antiinfective and an inhalation device. Formulating theantiinfective as a mixture of free and lipid-based compositionencapsulated antiinfective provides several advantages, some of whichinclude: (a) provides for a bolus of free antiinfective for immediatebactericidal activity and a sustained level of antiinfective forprevention of resistance; (b) simplifies the manufacturing process, asless free antiinfective need be removed via diafiltration; and (c)allows for greater antiinfective contents to be achieved in the drugproduct.

These embodiments of the present invention, other embodiments, and theirfeatures and characteristics, will be apparent from the description,drawings and claims that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts the plot of lung concentration (μg/ml) as a function oftime following nebulization of unencapsulated tobramycin at a nominaldose of 300 mg (TOBI®, Chiron Corp., Emeryville, Calif.), and liposomalamikacin at a nominal dose of 100 mg. Lung concentrations for both drugproducts are calculated assuming a volume of distribution foraminoglycosides in the lung of 200 ml. The tobramycin curve wasdetermined by pharmacokinetic modeling of the temporal tobramycin plasmaconcentration curve (Le Brun thesis, 2001).

DETAILED DESCRIPTION OF THE INVENTION

Definitions

For convenience, before further description of the present invention,certain terms employed in the specification, examples and appendedclaims are collected here. These definitions should be read in light ofthe remainder of the disclosure and understood as by a person of skillin the art. Unless defined otherwise, all technical and scientific termsused herein have the same meaning as commonly understood by a person ofordinary skill in the art.

The articles “a” and “an” are used herein to refer to one or to morethan one (i.e. to at least one) of the grammatical object of thearticle. By way of example, “an element” means one element or more thanone element.

The term “antibacterial” is art-recognized and refers to the ability ofthe compounds of the present invention to prevent, inhibit or destroythe growth of microbes of bacteria.

The terms “antiinfective” and “antiinfective agent” are usedinterchangeably throughout the specification to describe a biologicallyactive agent which can kill or inhibit the growth of certain otherharmful pathogenic organisms, including but not limited to bacteria,yeasts and fungi, viruses, protozoa or parasites, and which can beadministered to living organisms, especially animals such as mammals,particularly humans.

The term “antimicrobial” is art-recognized and refers to the ability ofthe compounds of the present invention to prevent, inhibit or destroythe growth of microbes such as bacteria, fungi, protozoa and viruses.

The term “bioavailable” is art-recognized and refers to a form of thesubject invention that allows for it, or a portion of the amountadministered, to be absorbed by, incorporated to, or otherwisephysiologically available to a subject or patient to whom it isadministered.

The terms “comprise” and “comprising” are used in the inclusive, opensense, meaning that additional elements may be included.

The term “illness” as used herein refers to any illness caused by orrelated to infection by an organism.

The term “including” is used herein to mean “including but not limitedto”. “Including” and “including but not limited to” are usedinterchangeably.

The term “lipid-based composition” as used herein refers to compositionsthat primarily comprise lipids. Non-limiting examples of lipid-basedcompositions may take the form of coated lipid particles, liposomes,emulsions, micelles, and the like.

The term “mammal” is known in the art, and exemplary mammals includehumans, primates, bovines, porcines, canines, felines, and rodents(e.g., mice and rats).

The term “microbe” is art-recognized and refers to a microscopicorganism. In certain embodiments the term microbe is applied tobacteria. In other embodiments the term refers to pathogenic forms of amicroscopic organism.

A “patient,” “subject” or “host” to be treated by the subject method maymean either a human or non-human animal.

The term “pharmaceutically-acceptable salts” is art-recognized andrefers to the relatively non-toxic, inorganic and organic acid additionsalts of compounds, including, for example, those contained incompositions of the present invention.

The term “prodrug” is art-recognized and is intended to encompasscompounds which, under physiological conditions, are converted into theantibacterial agents of the present invention. A common method formaking a prodrug is to select moieties which are hydrolyzed underphysiological conditions to provide the desired compound. In otherembodiments, the prodrug is converted by an enzymatic activity of thehost animal or the target bacteria.

The term “treating” is art-recognized and refers to curing as well asameliorating at least one symptom of any condition or disease.

Lipids

The lipids used in the pharmaceutical formulations of the presentinvention can be synthetic, semi-synthetic or naturally-occurringlipids, including phospholipids, tocopherols, sterols, fatty acids,glycoproteins such as albumin, negatively-charged lipids and cationiclipids. In terms of phosholipids, they could include such lipids as eggphosphatidylcholine (EPC), egg phosphatidylglycerol (EPG), eggphosphatidylinositol (EPI), egg phosphatidylserine (EPS),phosphatidylethanolamine (EPE), and phosphatidic acid (EPA); the soyacounterparts, soy phosphatidylcholine (SPC); SPG, SPS, SPI, SPE, andSPA; the hydrogenated egg and soya counterparts (e.g., HEPC, HSPC),other phospholipids made up of ester linkages of fatty acids in the 2and 3 of glycerol positions containing chains of 12 to 26 carbon atomsand different head groups in the I position of glycerol that includecholine, glycerol, inositol, serine, ethanolamine, as well as thecorresponding phosphatidic acids. The chains on these fatty acids can besaturated or unsaturated, and the phospholipid may be made up of fattyacids of different chain lengths and different degrees of unsaturation.In particular, the compositions of the formulations can includedipalmitoylphosphatidylcholine (DPPC), a major constituent ofnaturally-occurring lung surfactant. Other examples includedimyristoylphosphatidycholine (DMPC) and dimyristoylphosphatidylglycerol(DMPG) dipalmitoylphosphatidcholine (DPPQ anddipalmitoylphosphatidylglycerol (DPPG) distearoylphosphatidylcholine(DSPQ and distearoylphosphatidylglycerol (DSPG),dioleylphosphatidyl-ethanolamine (DOPE) and mixed phospholipids likepalmitoylstearoylphosphatidyl-choline (PSPC) andpalmitoylstearolphosphatidylglycerol (PSPG), and single acylatedphospholipids like mono-oleoyl-phosphatidylethanolamine (MOPE).

The sterols can include, cholesterol, esters of cholesterol includingcholesterol hemi-succinate, salts of cholesterol including cholesterolhydrogen sulfate and cholesterol sulfate, ergosterol, esters ofergosterol including ergosterol hemi-succinate, salts of ergosterolincluding ergosterol hydrogen sulfate and ergosterol sulfate,lanosterol, esters of lanosterol including lanosterol hemi-succinate,salts of lanosterol including lanosterol hydrogen sulfate and lanosterolsulfate. The tocopherols can include tocopherols, esters of tocopherolsincluding tocopherol hemi-succinates, salts of tocopherols includingtocopherol hydrogen sulfates and tocopherol sulfates. The term “sterolcompound” includes sterols, tocopherols and the like.

The cationic lipids used can include ammonium salts of fatty acids,phospholids and glycerides. The fatty acids include fatty acids ofcarbon chain lengths of 12 to 26 carbon atoms that are either saturatedor unsaturated. Some specific examples include: myristylamine,palmitylamine, laurylamine and stearylamine, dilauroylethylphosphocholine (DLEP), dimyristoyl ethylphosphocholine (DMEP),dipalmitoyl ethylphosphocholine (DPEP) and distearoylethylphosphocholine (DSEP),N-(2,3-di-(9-(Z)-octadecenyloxy)-prop-1-yl-N,N,N-trimethylammoniumchloride (DOTMA) and 1,2-bis(oleoyloxy)-3-(trimethylammonio)propane(DOTAP).

The negatively-charged lipids which can be used includephosphatidyl-glycerols (PGs), phosphatidic acids (PAs),phosphatidylinositols (Pls) and the phosphatidyl serines (PSs). Examplesinclude DMPG, DPPG, DSPG, DMPA, DPPA, DSPA, DMPI, DPPI, DSPI, DMPS, DPPSand DSPS.

Phosphatidylcholines, such as DPPC, aid in the uptake by the cells inthe lung (e.g., the alveolar macrophages) and helps to sustain releaseof the bioactive agent in the lung. The negatively charged lipids suchas the PGs, PAs, PSs and PIs, in addition to reducing particleaggregation, are believed to play a role in the sustained releasecharacteristics of the inhalation formulation as well as in thetransport of the formulation across the lung (transcytosis) for systemicuptake. The sterol compounds are believed to affect the releasecharacteristics of the formulation.

Liposomes

Liposomes are completely closed lipid bilayer membranes containing anentrapped aqueous volume. Liposomes may be unilamellar vesicles(possessing a single membrane bilayer) or multilamellar vesicles(onion-like structures characterized by multiple membrane bilayers, eachseparated from the next by an aqueous layer). The bilayer is composed oftwo lipid monolayers having a hydrophobic “tail” region and ahydrophilic “head” region. The structure of the membrane bilayer is suchthat the hydrophobic (nonpolar) “tails” of the lipid monolayers orienttoward the center of the bilayer while the hydrophilic “heads” orienttowards the aqueous phase.

Liposomes can be produced by a variety of methods (for a review, see,e.g., Cullis et al. (1987)). Bangham's procedure (J. Mol. Biol. (1965))produces ordinary multilamellar vesicles (MLVs). Lenk et al. (U.S. Pat.Nos. 4,522,803, 5,030,453 and 5,169,637), Fountain et al. (U.S. Pat. No.4,588,578) and Cullis et al. (U.S. Pat. No. 4,975,282) disclose methodsfor producing multilamellar liposomes having substantially equalinterlamellar solute distribution in each of their aqueous compartments.Paphadjopoulos et al., U.S. Pat. No. 4,235,871, discloses preparation ofoligolamellar liposomes by reverse phase evaporation.

Unilamellar vesicles can be produced from MLVs by a number oftechniques, for example, the extrusion of Cullis et al. (U.S. Pat. No.5,008,050) and Loughrey et al. (U.S. Pat. No. 5,059,421)). Sonicationand homogenization cab be so used to produce smaller unilamellarliposomes from larger liposomes (see, for example, Paphadjopoulos et al.(1968); Deamer and Uster (1983); and Chapman et al. (1968)).

The original liposome preparation of Bangham et al. (J. Mol. Biol.,1965, 13:238-252) involves suspending phospholipids in an organicsolvent which is then evaporated to dryness leaving a phospholipid filmon the reaction vessel. Next, an appropriate amount of aqueous phase isadded, the 60 mixture is allowed to “swell”, and the resulting liposomeswhich consist of multilamellar vesicles (MLVs) are dispersed bymechanical means. This preparation provides the basis for thedevelopment of the small sonicated unilamellar vesicles described byPapahadjopoulos et al. (Biochim. Biophys, Acta., 1967, 135:624-638), andlarge unilamellar vesicles.

Techniques for producing large unilamellar vesicles (LUVs), such as,reverse phase evaporation, infusion procedures, and detergent dilution,can be used to produce liposomes. A review of these and other methodsfor producing liposomes may be found in the text Liposomes, Marc Ostro,ed., Marcel Dekker, Inc., New York, 1983, Chapter 1, the pertinentportions of which are incorporated herein by reference. See also Szoka,Jr. et al., (1980, Ann. Rev. Biophys. Bioeng., 9:467), the pertinentportions of which are also incorporated herein by reference.

Other techniques that are used to prepare vesicles include those thatform reverse-phase evaporation vesicles (REV), Papahadjopoulos et al.,U.S. Pat. No. 4,235,871. Another class of liposomes that may be used arethose characterized as having substantially equal lamellar solutedistribution. This class of liposomes is denominated as stableplurilamellar vesicles (SPLV) as defined in U.S. Pat. No. 4,522,803 toLenk, et al. and includes monophasic vesicles as described in U.S. Pat.No. 4,588,578 to Fountain, et al. and frozen and thawed multilamellarvesicles (FATMLV) as described above.

A variety of sterols and their water soluble derivatives such ascholesterol hemisuccinate have been used to form liposomes; seespecifically Janoffet al., U.S. Pat. No. 4,721,612, issued Jan. 26,1988, entitled “Steroidal Liposomes.” Mayhew et al., PCT Publication No.WO 85/00968, published Mar. 14, 1985, described a method for reducingthe toxicity of drugs by encapsulating them in liposomes comprisingalpha-tocopherol and certain derivatives thereof. Also, a variety oftocopherols and their water soluble derivatives have been used to formliposomes, see Janoff et al., PCT Publication No. 87/02219, publishedApr. 23, 1987, entitled “Alpha Tocopherol-Based Vesicles”.

The liposomes are comprised of particles with a mean diameter ofapproximately 0.01 microns to approximately 3.0 microns, preferably inthe range about 0.2 to 1.0 microns. The sustained release property ofthe liposomal product can be regulated by the nature of the lipidmembrane and by inclusion of other excipients (e.g., sterols) in thecomposition.

Infective Agent

The infective agent included in the scope of the present invention maybe a bacteria. The bacteria can be selected from: Pseudomonasaeruginosa, Bacillus anthracis, Listeria monocytogenes, Staphylococcusaureus, Salmenellosis, Yersina pestis, Mycobacterium leprae, M.africanum, M. asiaticum, M. aviuin-intracellulaire, M. cheloneiabscessus, M. fallax, M. fortuitum, M. kansasii, M. leprae, M.malmoense, M. shimoidei, M. simiae, M. szulgai, M. xenopi, M.tuberculosis, Brucella melitensis, Brucella suis, Brucella abortus,Brucella canis, Legionella pneumonophilia, Francisella tularensis,Pneurnocystis carinii, mycoplasma, and Burkholderia cepacia.

The infective agent included in the scope of the present invention canbe a virus. The virus can be selected from: hantavirus, respiratorysyncytial virus, influenza, and viral pneumonia.

The infective agent included in the scope of the present invention canbe a fungus. Fungal diseases of note include: aspergillosis,disseminated candidiasis, blastomycosis, coccidioidomycosis,cryptococcosis, histoplasmosis, mucormycosis, and sporotrichosis.

Antiinfectives

The term antiinfective agent is used throughout the specification todescribe a biologically active agent which can kill or inhibit thegrowth of certain other harmful pathogenic organisms, including but notlimited to bacteria, yeasts and fungi, viruses, protozoa or parasites,and which can be administered to living organisms, especially animalssuch as mammals, particularly humans.

Non-limiting examples of antibiotic agents that may be used in theantiinfective compositions of the present invention includecephalosporins, quinolones and fluoroquinolones, penicillins, and betalactamase inhibitors, carbepenems, monobactams, macrolides andlincosamines, glycopeptides, rifampin, oxazolidonones, tetracyclines,aminoglycosides, streptogramins, sulfonamides, and others. Each familycomprises many members.

Cephalosporins

Cephalosporins are further categorized by generation. Non-limitingexamples of cephalosporins by generation include the following. Examplesof cephalosporins I generation include Cefadroxil, Cefazolin,Cephalexin, Cephalothin, Cephapirin, and Cephradine. Examples ofcephalosporins II generation include Cefaclor, Cefamandol, Cefonicid,Cefotetan, Cefoxitin, Cefprozil, Ceftmetazole, Cefuroxime, Cefuroximeaxetil, and Loracarbef. Examples of cephalosporins III generationinclude Cefdinir, Ceftibuten, Cefditoren, Cefetamet, Cefpodoxime,Cefprozil, Cefuroxime (axetil), Cefuroxime (sodium), Cefoperazone,Cefixime, Cefotaxime, Cefpodoxime proxetil, Ceftazidime, Ceftizoxime,and Ceftriaxone. Examples of cephalosporins IV generation includeCefepime.

Quinolones and Fluoroquinolones

Non-limiting examples of quinolones and fluoroquinolones includeCinoxacin, Ciprofloxacin, Enoxacin, Gatifloxacin, Grepafloxacin,Levofloxacin, Lomefloxacin, Moxifloxacin, Nalidixic acid, Norfloxacin,Ofloxacin, Sparfloxacin, Trovafloxacin, Oxolinic acid, Gemifloxacin, andPerfloxacin.

Penicillins

Non-limiting examples of penicillins include Amoxicillin, Ampicillin,Bacampicillin, Carbenicillin Indanyl, Mezlocillin, Piperacillin, andTicarcillin.

Penicillins and Beta Lactamase Inhibitors

Non-limiting examples of penicillins and beta lactamase inhibitorsinclude Amoxicillin-Clavulanic Acid, Ampicillin-Sulbactam, Sulfactam,Tazobactam, Benzylpenicillin, Cloxacillin, Dicloxacillin, Methicillin,Oxacillin, Penicillin G (Benzathine, Potassium, Procaine), Penicillin V,Penicillinase-resistant penicillins, Isoxazoylpenicillins,Aminopenicillins, Ureidopenicillins, Piperacillin+Tazobactam,Ticarcillin+Clavulanic Acid, and Nafcillin.

Carbepenems

Non-limiting examples of carbepenems include Imipenem-Cilastatin andMeropenem.

Monobactams

A non-limiting example of a monobactam includes Aztreonam.

Macrolides and Lincosamines

Non-limiting examples of macrolides and lincosamines includeAzithromycin, Clarithromycin, Clindamycin, Dirithromycin, Erythromycin,Lincomycin, and Troleandomycin.

Glycopeptides

Non-limiting examples of glycopeptides include Teicoplanin andVancomycin.

Rifampin

Non-limiting examples of rifampins include Rifabutin, Rifampin, andRifapentine.

Oxazolidonones

A non-limiting example of oxazolidonones includes Linezolid.

Tetracyclines

Non-limiting examples of tetracyclines include Demeclocycline,Doxycycline, Methacycline, Minocycline, Oxytetracycline, Tetracycline,and Chlortetracycline.

Aminoglycosides

Non-limiting examples of aminoglycosides include Amikacin, Gentamicin,Kanamycin, Neomycin, Netilmicin, Streptomycin, Tobramycin, andParomomycin.

Streptogramins

A non-limiting example of streptogramins includesQuinopristin+Dalfopristin.

Sulfonamides

Non-limiting examples of sulfonamides include Mafenide, SilverSulfadiazine, Sulfacetamide, Sulfadiazine, Sulfamethoxazole,Sulfasalazine, Sulfisoxazole, Trimethoprim-Sulfamethoxazole, andSulfamethizole.

Others

Non-limiting examples of other antibiotic agents include Bacitracin,Chloramphenicol, Colistemetate, Fosfomycin, Isoniazid, Methenamine,Metronidazol, Mupirocin, Nitrofurantoin, Nitrofurazone, Novobiocin,Polymyxin B, Spectinomycin, Trimethoprine,Trimethoprine/Sulfamethoxazole, Cationic peptides, Colistin, Iseganan,Cycloserine, Capreomycin, Pyrazinamide, Para-aminosalicyclic acid,, andErythromycin ethylsuccinate+sulfisoxazole.

Antiviral agents include, but are not limited to: zidovudine, acyclovir,ganciclovir, vidarabine, idoxuridine, trifluridine, ribavirin,interferon alpha-2a, interferon alpha-2b, interferon beta, interferongamma).

Anifungal agents include, but are not limited to: amphotericin B,nystatin, hamycin, natamycin, pimaricin, ambruticin, itraconazole,terconazole, ketoconazole, voriconazole, miconazole, nikkomycin Z,griseofulvin, candicidin, cilofungin, chlotrimazole, clioquinol,caspufungin, tolnaftate.

Dosages

The dosage of any compositions of the present invention will varydepending on the symptoms, age and body weight of the patient, thenature and severity of the disorder to be treated or prevented, theroute of administration, and the form of the subject composition. Any ofthe subject formulations may be administered in a single dose or individed doses. Dosages for the compositions of the present invention maybe readily determined by techniques known to those of skill in the artor as taught herein.

In certain embodiments, the dosage of the subject compounds willgenerally be in the range of about 0.01 ng to about 10 g per kg bodyweight, specifically in the range of about 1 ng to about 0.1 g per kg,and more specifically in the range of about 100 ng to about 10 mg perkg.

An effective dose or amount, and any possible affects on the timing ofadministration of the formulation, may need to be identified for anyparticular composition of the present invention. This may beaccomplished by routine experiment as described herein, using one ormore groups of animals (preferably at least 5 animals per group), or inhuman trials if appropriate. The effectiveness of any subjectcomposition and method of treatment or prevention may be assessed byadministering the composition and assessing the effect of theadministration by measuring one or more applicable indices, andcomparing the post-treatment values of these indices to the values ofthe same indices prior to treatment.

The precise time of administration and amount of any particular subjectcomposition that will yield the most effective treatment in a givenpatient will depend upon the activity, pharmacokinetics, andbioavailability of a subject composition, physiological condition of thepatient (including age, sex, disease type and stage, general physicalcondition, responsiveness to a given dosage and type of medication),route of administration, and the like. The guidelines presented hereinmay be used to optimize the treatment, e.g., determining the optimumtime and/or amount of administration, which will require no more thanroutine experimentation consisting of monitoring the subject andadjusting the dosage and/or timing.

While the subject is being treated, the health of the patient may bemonitored by measuring one or more of the relevant indices atpredetermined times during the treatment period. Treatment, includingcomposition, amounts, times of administration and formulation, may beoptimized according to the results of such monitoring. The patient maybe periodically reevaluated to determine the extent of improvement bymeasuring the same parameters. Adjustments to the amount(s) of subjectcomposition administered and possibly to the time of administration maybe made based on these reevaluations.

Treatment may be initiated with smaller dosages which are less than theoptimum dose of the compound. Thereafter, the dosage may be increased bysmall increments until the optimum therapeutic effect is attained.

The use of the subject compositions may reduce the required dosage forany individual agent contained in the compositions (e.g., the FabIinhibitor) because the onset and duration of effect of the differentagents may be complimentary.

Toxicity and therapeutic efficacy of subject compositions may bedetermined by standard pharmaceutical procedures in cell cultures orexperimental animals, e.g., for determining the LD₅₀ and the ED₅₀.

The data obtained from the cell culture assays and animal studies may beused in formulating a range of dosage for use in humans. The dosage ofany subject composition lies preferably within a range of circulatingconcentrations that include the ED₅₀ with little or no toxicity. Thedosage may vary within this range depending upon the dosage formemployed and the route of administration utilized. For compositions ofthe present invention, the therapeutically effective dose may beestimated initially from cell culture assays.

Pharmaceutical Formulation

The pharmaceutical formulation of the antiinfective may be comprised ofeither an aqueous dispersion of liposomes and free antiinfective, or adehydrated powder containing liposomes and free antiinfective. Theformulation may contain lipid excipients to form the liposomes, andsalts/buffers to provide the appropriate osmolarity and pH. The drypowder formulations may contain additional excipients to prevent theleakage of encapsulated antiinfective during the drying and potentialmilling steps needed to create a suitable particle size for inhalation(i.e., 1-5 μm). Such excipients are designed to increase the glasstransition temperature of the antiinfective formulation. Thepharmaceutical excipient may be a liquid or solid filler, diluent,solvent or encapsulating material, involved in carrying or transportingany subject composition or component thereof from one organ, or portionof the body, to another organ, or portion of the body. Each excipientmust be “acceptable” in the sense of being compatible with the subjectcomposition and its components and not injurious to the patient.Suitable excipients include trehalose, raffinose, mannitol,. sucrose,leucine, trileucine, and calcium chloride. Examples of other suitableexcipients include (1) sugars, such as lactose, and glucose; (2)starches, such as corn starch and potato starch; (3) cellulose, and itsderivatives, such as sodium carboxymethyl cellulose, ethyl cellulose andcellulose acetate; (4) powdered tragacanth; (5) malt; (6) gelatin; (7)talc; (8) excipients, such as cocoa butter and suppository waxes; (9)oils, such as peanut oil, cottonseed oil, safflower oil, sesame oil,olive oil, corn oil and soybean oil; (10) glycols, such as propyleneglycol; (11) polyols, such as glycerin, sorbitol, and polyethyleneglycol; (12) esters, such as ethyl oleate and ethyl laurate; (13) agar;(14) buffering agents, such as magnesium hydroxide and aluminumhydroxide; (15) alginic acid; (16) pyrogen-free water; (17) isotonicsaline; (18) Ringer's solution; (19) ethyl alcohol; (20) phosphatebuffer solutions; and (21) other non-toxic compatible substancesemployed in pharmaceutical formulations.

Inhalation Device

The pharmaceutical formulations of the present invention may be used inany dosage dispensing device adapted for intranasal administration. Thedevice should be constructed with a view to ascertaining optimummetering accuracy and compatibility of its constructive elements, suchas container, valve and actuator with the nasal formulation and could bebased on a mechanical pump system, e.g., that of a metered-dosenebulizer, dry powder inhaler, soft mist inhaler, or a nebulizer. Due tothe large administered dose, preferred devices include jet nebulizers(e.g., PARI LC Star, AKITA), soft mist inhalers (e.g., PARI e-Flow), andcapsule-based dry powder inhalers (e.g., PH&T Turbospin). Suitablepropellants may be selected among such gases as fluorocarbons,hydrocarbons, nitrogen and dinitrogen oxide or mixtures thereof.

The inhalation delivery device can be a nebulizer or a metered doseinhaler (MDI), or any other suitable inhalation delivery device known toone of ordinary skill in the art. The device can contain and be used todeliver a single dose of the antiinfective compositions or the devicecan contain and be used to deliver multi-doses of the compositions ofthe present invention.

A nebulizer type inhalation delivery device can contain the compositionsof the present invention as a solution, usually aqueous, or asuspension. In generating the nebulized spray of the compositions forinhalation, the nebulizer type delivery device may be drivenultrasonically, by compressed air, by other gases, electronically ormechanically. The ultrasonic nebulizer device usually works by imposinga rapidly oscillating waveform onto the liquid film of the formulationvia an electrochemical vibrating surface. At a given amplitude thewaveform becomes unstable, whereby it disintegrates the liquids film,and it produces small droplets of the formulation. The nebulizer devicedriven by air or other gases operates on the basis that a high pressuregas stream produces a local pressure drop that draws the liquidformulation into the stream of gases via capillary action. This fineliquid stream is then disintegrated by shear forces. The nebulizer maybe portable and hand held in design, and may be equipped with a selfcontained electrical unit. The nebulizer device may comprise a nozzlethat has two coincident outlet channels of defined aperture size throughwhich the liquid formulation can be accelerated. This results inimpaction of the two streams and atomization of the formulation. Thenebulizer may use a mechanical actuator to force the liquid formulationthrough a multiorifice nozzle of defined aperture size(s) to produce anaerosol of the formulation for inhalation. In the design of single dosenebulizers, blister packs containing single doses of the formulation maybe employed.

In the present invention the nebulizer may be employed to ensure thesizing of particles is optimal for positioning of the particle within,for example, the pulmonary membrane.

A metered dose inhalator (MDI) may be employed as the inhalationdelivery device for the compositions of the present invention. Thisdevice is pressurized (pMDI) and its basic structure comprises ametering valve, an actuator and a container. A propellant is used todischarge the formulation from the device. The composition may consistof particles of a defined size suspended in the pressurizedpropellant(s) liquid, or the composition can be in a solution orsuspension of pressurized liquid propellant(s). The propellants used areprimarily atmospheric friendly hydroflourocarbons (HFCs) such as 134aand 227. Traditional chloroflourocarbons like CFC-11, 12 and 114 areused only when essential. The device of the inhalation system maydeliver a single dose via, e.g., a blister pack, or it may be multi dosein design. The pressurized metered dose inhalator of the inhalationsystem can be breath actuated to deliver an accurate dose of thelipid-containing formulation. To insure accuracy of dosing, the deliveryof the formulation may be programmed via a microprocessor to occur at acertain point in the inhalation cycle. The MDI may be portable and handheld.

Exemplification EXAMPLE 1

Pharmacokinetics of amikacin delivered as both free and encapsulatedamikacin in healthy volunteers. The nebulized liposomal amikacincontains a mixture of encapsulated (ca., 60%) and free amikacin (ca.,40%). Following inhalation in healthy volunteers the corrected nominaldose was 100 mg as determined by gamma scintigraphy. FIG. 1 depicts thelung concentration of amikacin and TOBI® (administered 100% free), basedon pharmacokinetic modeling of serum concentrations over time. Bothcurves assume a volume of distribution for aminoglycosides in the lungof 200 ml. Interestingly, the peak levels of antiinfective in the lungare approximately equivalent for the 100 mg dose of liposomal amikacin,and the 300 mg dose of TOBI®. This is a consequence of the rapidclearance of the free, tobramycin from the lung by absorption into thesystemic circulation with a half-life of about 1.5 hr. These resultsserve as a demonstration of the improved lung targeting afforded byliposomal encapsulation. The presence of free and encapsulatedantiinfective in the amikacin formulation is demonstrated by the twocomponent pharmacokinetic profile observed. Free amikacin is rapidlyabsorbed into the systemic circulation (with a half-life similar toTOBI), while the encapsulated drug has a lung half-life of approximately45 hr. The free amikacin is available to provide bactericidal activity,while the encapsulated drug provides sustained levels of drug in thelung, enabling improved killing of resistant bacterial strains. Themeasured lung concentrations for the liposomal compartment aresignificantly above the MIC₅₀ of 1240 clinical isolates of Pseudomonasaeruginosa, potentially reducing the development of resistance.

EXAMPLE 2

Impact of free amikacin on the percentage of amikacin encapsulated inliposomes following nebulization. Liposomal preparations of amikacin mayexhibit significant leakage of encapsulated drug during nebulization. Asdetailed in Table I below, the presence of free amikacin in solution wasshown to surprisingly decrease the leakage of antiinfective by aboutfour-fold from the liposome. While not wishing to be limited to anyparticular theory, it is hypothesized that liposomes break-up andre-form during nebulization, losing encapsulated antiinfective in theprocess. Alternatively, encapsulated antiinfective is lost duringnebulization because the liposome membrane becomes leaky. When an excessof free antiinfective is present in solution, the free antiinfective isreadily available in close proximity to the liposome, and is availableto be taken back up into the liposome on re-formation. TABLE 1 Effect offree amikacin on the leakage of amikacin from liposome-encapsulatedamikacin. % Free Amikacin % Free Amikacin % Free Amikacin (Post- (Due toFormulation (Pre-nebulization) nebulization) nebulization) A 3.3 (n = 1)42.4 ± 3.2 (n = 3) 39.1 ± 3.2 (n = 3) B 53.6 ± 5.4 (n = 9) 63.3 ± 4.7 (n= 9)  9.8 ± 5.8 (n = 9)Wherein n is the number of measurements.

Incorporation by Reference

All of the patents and publications cited herein are hereby incorporatedby reference.

EQUIVALENTS

Those skilled in the art will recognize, or be able to ascertain usingno more than routine experimentation, many equivalents to the specificembodiments of the invention described herein. Such equivalents areintended to be encompassed by the following claims.

1. A system for treating or providing prophylaxus against a pulmonaryinfection comprising: a) a pharmaceutical formulation comprising amixture of free antiinfective and antiinfective encapsulated in alipid-based composition, wherein the amount of free antiinfective issufficient to provide for immediate bactericidal activity, and theamount of encapsulated antiinfective is sufficient to provide sustainedbactericidal activity and reduce the development of resistant strains ofthe infective agent, and b) an inhalation delivery device.
 2. The systemof claim 1, wherein the antiinfective is selected from the groupconsisting of antibiotic agents, antiviral agents, and antifungalagents.
 3. The system of claim 1, wherein the antiinfective is anantibiotic selected from the group consisting of cephalosporins,quinolones, fluoroquinolones, penicillins, beta lactamase inhibitors,carbepenems, monobactams, macrolides, lincosamines, glycopeptides,rifampin, oxazolidonones, tetracyclines, aminoglycosides,streptogramins, and sulfonamides.
 4. The system of claim 1, wherein theantiinfective is an aminoglycoside.
 5. The system of claim 1, whereinthe antiinfective is amikacin.
 6. The system of claim 1, wherein theantiinfective is gentamicin.
 7. The system of claim 1, wherein theantiinfective is tobramycin.
 8. The system of claim 1, wherein thelipid-based composition is a liposome.
 9. The system of claim 8, whereinthe liposome comprises a mixture of unilamellar vesicles andmultilamellar vesicles.
 10. The system of claim 8, wherein the liposomecomprises a phospholipid and a sterol.
 11. The system of claim 8,wherein the liposome comprises a phosphatidylcholine and a sterol. 12.The system of claim 8, wherein the liposome comprisesdipalmitoylphosphatidylcholine (DPPC) and a sterol.
 13. The system ofclaim 8, wherein the liposome comprises dipalmitoylphosphatidylcholine(DPPC) and cholesterol.
 14. The system of claim 8, wherein theantiinfective is an aminogylcoside and the liposome comprises DPPC andcholesterol.
 15. The system of claim 8, wherein the antiinfective isamikacin, the liposome comprises DPPC and cholesterol, and the liposomecomprises a mixture of unilamellar vesicles and multilamellar vesicles.16. The system of claim 1, wherein the ratio by weight of freeantiinfective to antiinfective encapsulated in a lipid-based compositionis between about 1:100 and about 100:1.
 17. The system of claim 1,wherein the ratio by weight of free antiinfective to antiinfectiveencapsulated in a lipid-based composition is between about 1:I0 andabout 10:1.
 18. The system of claim 1, wherein the ratio by weight offree antiinfective to antiinfective encapsulated in a lipid-basedcomposition is between about 1:2 and about 2:1.
 19. A method forproviding prophylaxis against a pulmonary infection in a patientcomprising administering an aerosolized pharmaceutical formulationcomprising the antiinfective to the lungs of the patient, wherein thepharmaceutical formulation comprises a mixture of free antiinfective andantiinfective encapsulated in a lipid-based composition, and wherein theamount of free antiinfective is sufficient to provide for bactericidalactivity, and the amount of encapsulated antiinfective is sufficient toreduce the development of resistant strains of the infectious agent. 20.The method of claim 19, wherein the method first comprises determiningthe minimum inhibitory concentration (MIC) of the antiinfective forinhibiting pulmonary infections, and wherein the amount of freeantiinfective is at least 2 times the MIC.
 21. The method of claim 20,wherein the amount of free antiinfective is at least 4 times the MIC.22. The method of claim 20, wherein the amount of free antiinfective isat least 10 times the MIC.
 23. The method of claim 20, wherein the ratioof the area under a lung concentration/time curve to the MIC at 24 hoursis greater than
 25. 24. The method of claim 20, wherein the ratio of thearea under a lung concentration/time curve to the MIC at 24 hours isgreater than
 100. 25. The method of claim 20, wherein the ratio of thearea under a lung concentration/time curve to the MIC at 24 hours isgreater than
 250. 26. The method of claim 19, wherein the antiinfectiveis selected from the group consisting of antibiotic agents, antiviralagents, and antifungal agents.
 27. The method of claim 19, wherein theantiinfective is an antibiotic selected from the group consisting ofcephalosporins, quinolones, fluoroquinolones, penicillins, betalactamase inhibitors, carbepenems, monobactams, macrolides,lincosamines, glycopeptides, rifampin, oxazolidonones, tetracyclines,aminoglycosides, streptogramins, and sulfonamides.
 28. The method ofclaim 19, wherein the antiinfective is an aminoglycoside.
 29. The methodof claim 19, wherein the antiinfective is amikacin.
 30. The method ofclaim 19, wherein the antiinfective is gentamicin.
 31. The method ofclaim 19, wherein the antiinfective is tobramycin.
 32. The method ofclaim 19, wherein the lipid-based composition is a liposome.
 33. Themethod of claim 32, wherein the liposome comprises a mixture ofunilamellar vesicles and multilamellar vesicles.
 34. The method of claim32, wherein the liposome comprises a phospholipid and a sterol.
 35. Themethod of claim 32, wherein the liposome comprises a phosphatidylcholineand a sterol.
 36. The method of claim 32, wherein the liposome comprisesdipalmitoylphosphatidylcholine (DPPC) and a sterol.
 37. The method ofclaim 32, wherein the liposome comprises dipalmitoylphosphatidylcholine(DPPC) and cholesterol.
 38. The method of claim 32, wherein theantiinfective is an aminogylcoside and the liposome comprises DPPC andcholesterol.
 39. The method of claim 32, wherein the antiinfective isamikacin, the liposome comprises DPPC and cholesterol, and the liposomecomprises a mixture of unilamellar vesicles and multilamellar vesicles.40. The method of claim 19, wherein the ratio by weight of freeantiinfective to antiinfective encapsulated in a lipid-based compositionis between about 1:100 and about 100:1.
 41. The method of claim 19,wherein the ratio by weight of free antiinfective to antiinfectiveencapsulated in a lipid-based composition is between about 1:10 andabout 10:1.
 42. The method of claim 19, wherein the ratio by weight offree antiinfective to antiinfective encapsulated in a lipid-basedcomposition is between about 1:2 and about 2:1.
 43. The method of claim19, wherein the aerosolized pharmaceutical formulation is administeredat least once a week.
 44. The method of claim 19, wherein the pulmonaryinfection is selected from the group consisting of cystic fibrosis,chronic obstructive pulmonary disease (COPD), bronchiectasis, acterialpneumonia, acute bronchial exacerbations of chronic bronchitis (ABECB),Mycobacterium tuberculosis, infections caused by inhaled agents ofbioterror, and opportunistic fungal infections.
 45. A method of reducingthe loss of antiinfective encapsulated in a lipid-based composition uponnebulization comprising administering the antiinfective encapsulated ina lipid-based composition with free antiinfective.